Telephone apparatus.



H. C. EGERTON. TELEPHONE APPARATUS. APPucATloN FILED APR. 20, 1914.

l 9 l @@,U lalfented June 20, 15H6.

gully/411442* i rrhh amarres raiiaia'r orribia HENRY C. EG-ZERTON, v02E' PASSAIG, NEW JERSEY, ASSIGNOR, BY MESNE ASSIGNMENTS, TO WESTERN 4EIEECIRIC COMPANY, INCORPORATED, A CORPORATION. OF NEW YORK.

indiaanse.

T all whom it mag/.concern Be it known that I, HENRY C. EGERTON, .,f a citizen of the United States, residing at Passaic, in the county of Passaic andtate `5 of New Jersey, have invented acertain new and useful Improvement in Telephonic Apparatus, of whichthe following is a full,

clear, concise, and eXact description.

This invention relates to telephonie appa-- ratus, and more particularly to telephone transmitters. 1

The object of this invention is to provide a new and improved transmitter of few' and' simple parts,.which will be highly sensitive to sound waves and capable of carrying a comparatively: large current for a considerable period `of time. The transmitter of this inventionlis microphonic in structure,

that is, the sound-receiving diaphragm is the details of the casing for rendering it,I

moistureproofA and other combinationsof parts and details of construction.

ln the drawings-Figure 1 is a sectional view of a transmitter embodying this in,- vention; and F-ig. 2 is a detail perspective view of parts of the device before assembly. Asshown in the drawing, 5 is a transmitter mouthpiece of ordinary form secured to a front member 6 of a casing comprising the front member 6 and aback/ member 7. The back member is composed of two members 8 and 9- separated and bent over at their margins to form an annular chamber within which the margin '.of the l front member 6 is inserted. A rubber gasket 10 is inserted between -the adjacent faces of the front and back members 6 and 7 for the purpose of rendering-the interior `of the casing moistureproof.

Locatedl within the casing in operative relation to the mouthpiece is a diaphragm .TELEPHONE ArrAnATU-s.

Specification of Letters Patent. Pmbutdl Jun@ 2U, 1916 .f

Application filed April 20, 1914. Serial No. 833,228.

15, preferably of carbon, which is insulated E15 from the casing member 6 by means of insulating members 16 and 17. Located within the casing and in the rear of the dia- Aphragm 15 is a supporting plate 18 having formed centrally thereof a cylindrical portion 19' for the purpose of receiving a granulecontaining chamber, as will hereinafter more fully appear. Aswill be noted, the supporting plate 18 iscupped, as shown. at 20,' adjacent the. cylindrical portion 19, 65 and is provided with a plurality of openings A21, 21 to lform a web of the cupped portion. This lcupped portion 20 faces thediaphragm and is adapted to bow backwardly therefrom in response to a heating of the granule container, thus separating the granular material and increasing the resist' ance through it.

Located within the cylindrical portion319. is a granule-containing cup 25, the forward '75 margin of which is tapered or chamfered od away from the inner edges, as shown at 26. Located within said container and bearing against a shoulder 27 therein is an electrode 28. This electrode :is secured in place by 8() means of a cupped spring 29 interposed between the electrode 28 and a closure 39,.' which is secured to the rear edge of the cylindrical member 19.y The front edge of the cylindrical memberl 19 is recessed as shown 85 at 35 to receive a washer 36 offelt or other suitable materialvagainst which the front vedge of thcontainer 25 also bears. Located within the chamber Atermed -between the front face of the electrode 28 and the rear 90 face of the `diaphragm 15 is a quantity of granular material 37 which lconstitutes the` resistance-varying medium 'of the device; The interior of this chamber has its lwall covered withfa thin layer of insulating japan '38 which, although it forms sufficient insulation against the current throughthe granular carbon, permits the heat generated by the current to pass through. As shown,

the felt1 ring or Washer 36 is comparatively 100 thi'n's that a -greater portion of the granular' material 37 is in contactwith the interior of the chamber than with felt ring so that the heat vgenerated therein will be readily conducted through the walls of the container 25 and the cylindrical portion 19 to the plate 18.

A spacer 40 1s inserted between the front face. of the plate and the rear face of the diaphragm "15,-A and'is insulated from the plate 18'- by means ofan insulating Washer 41. Terminal binding posts 45 .and 46 are secured to theplate 18, the post 45 bein insulatedfrom said platel but in electrica contact 'with the'spacer 40 and thus with the diaphragml, the post 46 being in electrical contact with the plate 18y only. These twoposts comprise the terminalsy of the device.

1. In a telephone transmitter, `a dia# -v phragm, I Va, resistance-varying medium 511i contact Withs'aid diaphragm, a container for said resistance-varying medium, anda thermostatic member carrying" said t:`Q11.-'v

Yfor said resistance-varying medium, and a Supporting member carryingsaid contai'ner and responsive to the heat generated therein, said supporting member dished to 4bow away from the diaphragm Whenheated.

In Witness whereof, I hereunto subscribe my name this 16 day'of April IA. D. 1914.

HENRY e. EGERTON.-

`Witnesses: 4 EDLER,

N., E. TnfrHILL. 

